1. Field of the Invention
The present invention relates to a body structure of a vehicle. More particularly, it relates to the body structure for an automotive front suspension attachment member whose vicinities are formed into one casting body of light metal or the like.
2. Description of Related Art
As the above-mentioned body structure where the suspension attachment member and the vicinities are integrally formed by a casting of light metal etc., there is a conventional body structure disclosed in Japanese Patent Unexamined Publication (kokai) No. 6-329050.
In the body structure, a suspension attachment member and a hood-ridge upper member are formed into one casting body of light metal, such as aluminum alloy. In assembly, the suspension attachment member is attached to a suspension suspended from a vehicle body to carry a vehicle wheel. Similarly, a housing member is formed of a casting of light metal, such as aluminum alloy. In assembly, the suspension attachment member and the hood-ridge upper member as one body are welded to the housing member.
Thus, when the vehicle body is made from castings of light metals, it is possible to reduce the number of components and the weight of the vehicle body.
In the above-mentioned body structure, however, the housing member is another element than one casting body having of the suspension attachment member and the hood-ridge upper member, persistently. Therefore, it has been required to weld the housing member to the suspension attachment member and the hood-ridge upper member on a factory's main line to produce the vehicle bodies, causing the problem of a troublesome welding work.
Moreover, since the hood-ridge upper member of the above body structure is shaped so as to open downward (i.e. inverse U-shaped cross section), to ensure the member's bending rigidity against a force exerted on the suspension, namely, suspension input requires to increase a plate thickness of the upper wall constituting the hood-ridge upper member. Therefore, there is a limit of the vehicle body to be light-weighted.